Tool for mechanically and electrochemically machining the surface of metallic workpieces

ABSTRACT

A tool for mechanically and electrochemically machining the surfaces of metallic workpieces in which a cylindrical body has distributed thereabout in alternating relation mechanical tool elements and electrochemical tool elements. The tool elements are radially moveable on the body and respective actuators are provided therefor with a slip clutch between the actuators so that when the electrochemical tool elements stop on the workpiece surface, the mechanical elements can continue radially outward feed movement.

llnite States atent 11 1 Gehring et a1.

TOOL FOR MECHANICALLY AND ELECTROCHEMKCALLY MACHINING THE SURFACE OFMETALLIC WORKPIECES Inventors: Christoph W. Gehring, Nellingen;

Egbert Scholz, Hannover; Wolfgang Strauss, Nurtingen, all of GermanyAssignee: Maschinenfabrik Gehring K.G. Nellingen, Germany Filed: Nov. 2,1971 Appl. No.1 195,071

Foreign Application Priority Data Nov. 26, 1970 Germany P 20 58 114.0

U.S. Cl. 204/217, 204/129.46, 204/224 M, 204/280, 204/286 Int. Cl B23p1/14, 823p 1/04 Field of Search 204/143 M, 224 M, 204/217, 280, 129.35,129.46, 224 M, 280, 217, 286

Primary ExaminerF. C. Edmundson AttorneyWalter Becker [57] ABSTRACT Atool for mechanically and electrochemically machining the surfaces ofmetallic workpieces in which a cylindrical body has distributedthereabout in alternating relation mechanical tool elements andelectrochemical tool elements. The tool elements are radially moveableon the body and respective actuators are provided therefor with a slipclutch between the actuators so that when the electrochemical toolelements stop on the workpiece surface, the mechanical elements cancontinue radially outward feed movement.

33 Claims, 3 Drawing Figures T001. FOR MECHANICALLY ANDELECTROCHEMHCALLY MACHINING THE SURFACE OF METALLIC WORKIIECES With anelectrochemical honing process, material is electrochemically taken offfrom the bore wall of the workpiece arranged as anode, and the surfaceof the workpiece is freed from a possibly existing passive layer andplaned by the simultaneously engaged honing stones. The electrochemicalmaterial removal is in conformity with Faradays law M= (l/96,500) (A/n)I t proportional to the charge Q, i.e. proportional to the current I andtime [.For the current I Ohrns law reads in which R stands for theresistance offered by the electrolyte stroke in the gap between theworkpiece surface and the cathode surface to be machined, in other wordsof the electrolytically effective working surface. From these giveninterrelations, there results the tendency to work with as narrow gapsas possible of the size of from 0.0 to imeter 9 d?! o bta nrra. maximumof precision and material removal.

With surfaces which have to be machined with honing additions of morethan 0.5 millimeters with regard to the diameter, therefore, the methodof employing the honing broaching body itself as cathode or to useseparate cathode segments fixedly connected to the honing broachingbody, is no longer suitable.

When the electrodes or cathode segments are automatically fed, forinstance, by springs or centrifugal forces, the great advantage isobtained that major form errors of the workpieces, for instance, withregard to oval shape conical shape, or the like, can no longer beeliminated inasmuch as the individual electrodes move in conformity withthe undesired form of the machining surface.

It is, therefore, an object of the present invention to provide a toolof the above mentioned general type which is so designed that in spiteof a simple construction, it will assure a precise setting of theelectrolytically effective working surface.

This object and other objects and advantages of the invention willappear more clearly from thefollowing specification, in connection withthe accompanying drawing, in which:

FIG. 1 illustrates a section through a honing tool according to thepresent invention, said section being taken along the line II of FIG. 2.

FIG. 2 is a section taken along the line IIII of FIG. 1, but on a largerscale than the latter.

FIG. 3 shows the front end of a further embodiment of a honing tool, andmore specifically, representsan axial section similar to that of FIG. 1.

The tool for mechanically and electrochemically surface machining ofmetallic workpieces with an electrolytically and a mechanical workingsurface, especially a working surface operating in a honing manner,which working surfaces are respectively arranged on separate toolelements which are mounted on a tool body and adapted to be fedtransverse to the working surfaces by different amounts is, inconformity with the present invention, characterized primarily in thatthe electrolytically effective tool element is, in its respective setworking position, secured with regard to movements in feeding direction.The electrolytically effective tool element will, in this way, not allowa changing course of the maching surface so that, for instance when abore is to be machined, a precisely cylindrical machining surface willbe obtained.

According to a further feature of the invention, the electrolyticallyeffective tool element is, in its moving direction, under spring load,supported with a counter surface by a setting surface of the pertainingfeeding device while the tool element preferably opposite to the feedingdirection is, by a spring load which is greater than the occurringcentrifugal forces, supported by the setting surface, so that in asimple manner, an aligning of the tool element can be effected.

For actuating the feeding device in a simple manner, the setting surfaceis adjustable substantially in the direction of the tool axis while thesetting surface and/or the counter surface are inclined to the axis ofthe tool so that by an axial movement of the setting surface a radialmovement of the electrolytically effective tool element will be created.

In particular, in order to cause the setting surface to engage thecounter surfaces of all electrolytically effective tool elementsdistributed over the circumference, the setting surface is at leastpartially conical whereby it will be assured that it can, for avoiding aunilateral wear, be rotated relative to the tool body. For purposes ofobtaining an extremely precise uniform feed of the electrolyticallyeffective tool element over the entire axial extension thereof, aplurality of setting surfaces, preferably at uniform distances, areserially arranged in the axial direction of the tool.

When the setting surface and/or the counter surface extend in thedirection toward the tool end which faces away from the clamping end, atan incline away from the working surface, the actuating bar may, in asimpler manner than from the connecting end of the workpiece, bearranged, for instance, as a pressure bar operable by a bar in themachine spindle, which pressure bar does not have to be connected to thebar in the machine spindle by separate coupling elements.

For purposes of further simplifying the construction of the tool, thesetting surface is provided on a sleeveshaped or similar setting elementwhich is connected to the actuating bar, preferably by means of at leastone radial pin.

In order to make sure that the electrolytically effective workingelements are, in each instance, safely guided and aligned, the settingelement, preferably in its moving direction pertaining to the feedingdirection comprises directly behind the setting surface a guidingsurface for the arrangement along a running surface of the tool body,said guiding surface preferably being formed by a cylinder mantle. Thecounter surface asso ciated with the setting surface may, in a simplemanner, be provided on that edge of the tool element which faces awayfrom the working surface.

For a safe mount, the electrolytically effective tool element is, bymeans of a preferably strip-shaped sliding element mounted in guidingmeans which are advantageously formed by an axial slot of the tool body.

In order to obtain a large electrolytically effective working surface,said working surface is mantle segment-shaped and preferably is formedby a circular ring segment which, for purposes of an easy assembly ofthe tool is connected to the sliding element; Expediently, that innersurface of the mantle segment which faces away from the working surfaceis, for purposes of selfstabilization, for the whole surface arrangementarranged on the circumference of the tool body so that, in completelyreturned condition it is supported safely and can hardly be damaged byouter mechanical influences. The said mantle segment is preferablyarranged symmetrically with regard to the axial plane of the tool, whichaxial plane passes through the sliding element.

It is particularly advantageous to arrange a plurality ofelectrolytically effective working surfaces, especially in even number,uniformly around the axis of the tool, preferably between each twomechanically effective working surfaces so that when viewing incircumferential direction, mechanically and electrolytically workingsurfaces alternate, and a high material removal can be obtained.

For purposes of obtaining an always constant working gap, i.e. an alwaysconstant distance between the electrolytically effective working surfaceand the workpiece surface being machined, the electrolytically effectivetool element has at least a spacer member which protrudes beyond thepertaining working surface and which preferably consists ofelectrolytically nonconductive material for the arrangement on thesurface to be machined. The extent to which the spacer member protrudesbeyond the electrolytically effective working surface determines thewidth of the working gap which may amount, for instance, to from 0.05 to0.5 millimeters.

For purposes of obtaining a very stable movement of the tool and torealize a uniform gap over the entire extension of the electrolyticallyeffective working surface, there is provided a plurality of spacermembers in the direction of the tool axis and/or in the direction of thecircumference on and distributed over the electrolytically effectiveworking element. Preferably, a plurality of spacer members are, eachtime, aligned in one of the two directions, especially in the directionof the tool axis. However, it is also advantageous to provide exclusiveor additionally, spacer members in the direction of the tool axisadjacent to the electrolytically effective working surface, because insuch an instance, a guiding will also be assured when the cathodesurfaces prior to the reversal of the stroke of the tool completelyleave the bore to be machined.

The spacer member which preferably is fastened in a recess, forinstance, by an adhesive may be formed by a precious stone,'forinstance, a ruby ball, a sapphire, a diamond, or the like, by analuminum oxide ceramic plate, a plate of synthetic or other materialwhich is electrically non-conductive. The material is expediently soselected that the spacer member will have good sliding properties.

The tool according to the invention may also be designed for machiningof surfaces by means of very small diameter, when the feeding device isprovided in the tool body and preferably comprises an actuating bar inthe axis of the tool.

According to a further suggestion in conformity with the invention,there is provided at least one annular spring which extends around thetool axis and which engages all electrolytically effective toolelements. By means of said annular spring, the electrolyticallyeffective tool elements are, in response to a corresponding movement oftheir setting surfaces moved into their returned position. However, itis also possible to load the electrolytically effective working elementsin feeding direction with at least one spring.

For purposes of obtaining a safe and simple feeding, there is in thepower path of the feeding device provided a friction coupling,especially a friction clutch, which is adjustable with regard to thefollower resistor, so that in response to an actuation of the feedingdevice, the spacer elements will, at a predetermined pressure, bepressed against the workpiece surface being machined. Thereupon, inresponse to a further actuation of the feeding device, a slip will occurin the friction clutch means, as a result of which a still strongerpressing on the spacer elements will be prevented. The said couplingmeans may be ofa mechanical, hydraulic, pneumatic, electric, or magneticdesign.

According to a particularly advantageous embodiment of the invention,the coupling part on the actuating side of the friction clutch isprovided with a control device for at least one tool element which isadjustable transverse to the working surface and is mounted on the toolbody. Preferably, such connection is a positive connection. The toolelement has the mechanically effective working surface so that inresponse to an actuation of the adjusting or control device, themechanically effective tool element can be fed at will by a frictionalengagement, whereas the electrolytically effective tool element willfollow this feeding movement through the friction clutch only until inthe described manner the spacer members are at a predetermined pressure,pressed against the workpiece surface being machined. This isparticularly advantageous, inasmuch as the mechanically effective toolelements in the course of the machining of the workpiece surface areworn to a considerably greater extend than spacer members so that themechanically effective tool elements have to be fed by greater distancethan the electrolytically effective tool elements.

According to another embodiment of the invention which is highlyadvantageous, the adjusting device has at least one setting surfacewhich is adjustable in the direction of the tool axis and engages acounter surface of the mechanically effective tool element. At least oneof these two surfaces lies, in conformity with the setting surfaceand/or the counter surface of the feeding device for theelectrolytically effective tool element, at an incline to the tool axis.A particularly favorable construction is obtained when in the axialdirection of the tool, alternately a setting surface for the mechanicaland a setting surface for the electrolytically effective tool element isprovided so that both tool elements, with reference to the axialdirection of the tool, are uniformly supported by the setting surfaces.Inasmuch as the mechanically effective tool element is, during themachining exposed to a higher load than the electrolytically effectiveworking element, it is expedient to provide one setting surface more forthe mechanically effective tool than for the electrolytically effectiveworking element so that there is obtained, for instance, an even numberof setting surfaces for the electrolytically effective tool element andan odd number of setting surfaces for the mechanically effective toolelement.

According to a particularly simple embodiment of the invention thesetting device is substantially ofthe same construction as the feedingdevice.

Particularly in this instance, the actuating bars of the feeding deviceand of the setting or control device can safely be mounted one withinthe other, preferably in a space saving and telescopic manner. Inparticular, the actuating bar for the feeding device should lie on theinside and its respective setting member should by a pin, or the like,extending through at least an axial slot of the outer actuating bar, beconnected to the inner actuating bar so that the setting elements of thesetting device and of the feeding device can be moved relative to eachother in the direction of the tool.

For purposes of obtaining a space savingconstruction, the clutchaccording to the invention is provided with a clutch sleeve, or thelike, which is at least in the feeding direction, positively connectedwith an actuating bar, especially the actuating bar of the adjustingdevice. The friction element of the clutch rests against the clutchsleeve. Expediently, the friction clutch element is formed by a frictionsleeve arranged in the clutch sleeve. The friction sleeve surrounds theactuating bar of the feeding device in a frictional engagementtherewith.

in order to set the follower resistance of the clutch, the toolaccording to the present invention may preferably be equipped with anaxially movable clamping member for the frictional member of the clutch.This clamping member may be formed preferably by a spindle sleeve whichis guided in an inner thread of the clutch sleeve having an outerthread, said spindle sleeve surrounding the actuating bar of the feedingdevice and is operable from the outside of the tool while assuring aprecise setting.

According to another embodiment of the invention, the frictional elementof the friction clutch is formed by at least one clamping body,especially a roller blocking ring, the clamping bodies of which restagainst a cone, or the like, located within the clutch sleeve and Comnected to the actuating bar of the feeding device. For purposes ofobtaining a precisely predetermined follower force of the frictionclutch, the clamping body and the cone, or the like, are for the mutualfollower position spring loaded in particular by a pressure spring whichrests against the major end face of the cone, or the like, on one handand an end face of a cage for the clamping body on the other side. Bychanging the preload of the spring, it is possible to vary the followerforce of the friction clutch.

in order to make sure that for actuation of the feeding and settingdevice, the actuating bar has to be actuated in one direction only, forinstance, by the bar in the machine spindle, the actuating bar is, in adirection counter to the feeding direction, spring loaded, preferably bya pressure spring on the end face of the clutch sleeve.

If the friction clutch is in axial direction located adjacent to thatsection of the tool which comprises the working surfaces, preferably islocated on that end which faces away from the clamping end of the tool,the friction clutch may be arranged in a simple manner also when thetool has a very small diameter.

For purposes of obtaining a particularly favorable relationship betweenthe mechanical and electrolytical material removal, the electrolyticallyeffective working surface extends in the axial direction of the toolover a, for instance, less than half the portion of the axial extensionof the mechanically effective working surface. The electrolyticallyeffective working surface is preferably located symmetrically withregard to the center of the axial extension of the mechanicallyeffective working surface. As a result thereof, it is possible in asimple manner in the axial direction of the tool and adjacent to theelectrolytically effective working surface to provide at leastoneguiding and/or spacer member. The guiding surface of said guiding and/orspacing member is preferably located in the continuation of the slidingsurface of the spacer member which is provided within the range of theelectrolytically effective working surface so that during the machiningoperation the spacer members as well as the guiding members engage thesurface being machined and on one hand determines the width of theworking gap and on the other hand contribute to stabilizing and aligningthe tool relative to the surface being machined.

For purposes of obtaining a very high guiding precision, the guidingelement is formed by a strip, the guiding surface of which, is constantas to the width, of the mechanically effective working surface. Theguiding elements which consist in particular of electricallynonconductive material may in a simple manner be connected directly tothe pertaining sliding member, preferably in a recess.

For further improvement of the guiding means of the tool, in axialdirection on both sides of the electrolytically effective workingsurface, guiding and/or spacing members are provided. These guidingand/or spacing members have those ends thereof which face away from theelectrolytically effective working surface extend in axial direction asfar as the pertaining ends of the mechanically effective workingsurface. Espediently, the guiding end or spacer member is symmetricallyarranged with regard to the central plane passing through the tool axisand pertaining to the respective electrolytically effective tool elementwhereby the guiding of the tool is further improved.

In order to avoid undesired electrochemical removal of material ofmaterial which removal might negatively affect the obtainable geometryof the workpiece surface to be machined, to tool body is, with theexception of the working surfaces and guiding surfaces, coveredsubstantially completely with an electrical insulation connectedthereto. This insulation is preferably formed by insulating sleeveswhich preferably in the axial direction of 'the tool are adjacent toboth sides of the working surfaces, and is further formed by insulatingsleeve segments located between the guiding surfaces and themechanically effective working surfaces, and is furthermore formed by aninsulating cap arranged at that endof the tool body which faces awayfrom the clamping end of the tool. For simplifying the setting of thetool, the actuating bar of the feeding device and/or the clampingmemberof the friction clutch freely protrude beyond that end of the tool whichfaces away from the clamping end and preferably is guided by a bore inthe insulating cap.

The insulating sleeves may in a simple manner be so designed that theyextend'over the two annular springs adjacent to the axial ends of theworking surfaces.

In order to'obtain a particularly loss-free current conduction to theelectrolytically effective working surface, the pertaining tool elementis connected to at least one highly flexible electric conductor,especially a copper strand. Expediently, the electric conductor is onone hand, connected to the sliding element of the electrolyticallyeffective tool element which consists of an electrically good conductoras, for instance, brass, and on the other hand is connected to theelectrically conductive tool body so that the electric conductor can bedesigned very short. Moreover, in this way, it will be assured thatwithout affecting the electrically conductive connection, the toolelements forming the electrolytically effective working surface canbeexchanged. According to a particularly advantageous embodiment of theinvention, the pertaining end of the electric conductor which forpurposes of obtaining an easy movability extends approximately parallelto the axis of the tool is inserted into a bore at the end of theelectrolytically effective tool element and is preferably solderedthereto. The electric conductor outside the tool element extends inparticular in an axial groove of the tool body which is covered by thepertaining insulating sleeve, so that the electric conductor in no wayimpedes the movability of the electrolytically effective tool element.

For connecting the tool through a connecting tool or directly to amachine spindle, the end of the tool body which is clamped in andpreferably is formed by a clamping cone has an electric contact surface,as a result of which a large contact surface is obtained. This contactsurface practically permits a loss-free transfer of high electriccurrents to the tool body. In particular, adjacent to the contactsurface there is provided a trapezoidal thread, or the like, forclamping the tool fast.

Referring now to the drawings in detail, FIGS. 1 and 2 show a honingtool according to the invention which is equipped with a tool body 1formed by a rotatable part. The tool body 1 has its rear end providedwith a clamping cone 2, for instance, of the self-locking type, and isfurthermore provided with an adjacent trapezoidal thread, section 3 andwith a collar 4 which in axial direction follows the thread section 3.The collar 4 has axial grooves 5 for tightening and loosening the'tool.

The tool body 1 adjacent to the collar 4 and at the front end has asubstantially cylindrical section 6, 7 respectively. These sections 6, 7have the same diameter, and therebetween there is provided asubstantially cylindrical central section which has a diameter reducedover that of the sections 6, 7. The central section 8 of the tool body 1has axial slots which are uniformly distributed over the circumference.In this specific instance shown, there are provided eight substantiallyidentical axial slots 9, 10 which are offset with regard to each otherby 45. Co-axially with the tool axis 11 there is provided in the toolbody 1 a bore 12. The central portion 8 of bore 12 comprises a section13 which is substantially cylindrical. The axial slots 9, 10 extend tothe inner surface of said section 13.

Strip-shaped sliding members 14, 15 of substantially the same structureare, in a play-free manner, radially displaceably inserted into axialslots 9, 10..The sliding members 14, 15 extend over the entire length ofthe central section 8 and are in axial direction substantially in aplay-free manner provided between those end faces of the sections 6, 7which face each other. The height of the sliding strips 14, 15substantially corresponds to the thickness of the wall of the centralsection 8 of the tool body.

'Arranged on the radial outer edges of the sliding strips 14,15 thereare provided honing stones 16 for forming mechanically effective workingsurface section 17, and annular ring segments 18 for formingelectrolytically effective working surface section 19. The arrangementis such that in circumferential direction between each two mechanicallyeffective working surfaces 17 provided on the sliding strips 14, thereis arranged on a sliding strip 15 an electrolytically effective workingsurface 19. The mechanically effective working surfaces 17 are formingnarrow strips, whereas the electrolytically effective working surfaces19 extend over an arc angle of approximately each. The annular ringcathode segments 18, however, are so designed that their side edges arelocated just outside the stroke of movement of the adjacent slidingstrips 14 provided with honing stones 16 so that said cathode segments18 do not impede said sliding strips 14 with regard to their slidingmovement. The strip-shaped honing stories 16 which extend approximatelyover the entire axial extension of the central section 8 of the toolbody may, for instance, in an adherent manner be connected with thepertaining sliding strip 14. On the other hand, the cathode segments 18which, similar to the honing stone 16, are respectively symmetricallyarranged to the pertaining sliding strip are connected to therespectively pertaining sliding strip 15 by means of screws 20 which inaxial direction are arranged one behind the other. The screw heads arecountersunk so that they are located deeper than the electrolyticallyeffective working surface 19. Thus, the cathode segments 18 can bedisengaged from the pertaining sliding strips 15 and can thus beexchanged. The axial extension of the cathode segments 18 is less thanhalf the actual extension of the honing stones 16. However, thearrangement is such that the entire electrolytically effective workingsurface 19 is considerably greater than the entire mechanicallyeffective working surface 17. The cathode segments 18 are locatedsymmetrically with regard to the center of the length of the centralsection 8 of the tool body or of the honing stones 16 which in axialdirection adjacent to each cathode segment 18 on both sides there is oneguiding strip 21 each connected to the pertaining sliding strip 16, forinstance, by means of adhesion. The guiding strips 21 which in crosssection corresponding approximately to the cross section of the honingstone 16 protrude with their guiding surfaces 22 by approximately 0.05to 0.5 millimeters beyond the cylinder mantle formed by theelectrolytical working surface 19 and are arranged symmetrically withregard to the axial plane of the tool which passes through therespective pertaining sliding strip 15. The guiding strips 21 extend inthe axial direction of the tool in slightly spaced relationship to therespective pertaining cathode segment 18 and with those ends thereofwhich face away from said cathode segments extend in axial direction ofthe tool as far as the honing stone l6. Aside from the guiding andspacer strips 21, guiding and spacer elements 23 are connected directlyto the cathode segments 18. The sliding surfaces 24 of said elements 23are located in the cylinder mantle in which the guiding surfaces 20 ofthe guiding strip 21 are provided. The spacer members 23 are, forinstance, by adhesive means connected to corresponding recesses 25 inthe electrolytically effective working surface 19 and'are locatedsymmetrically with regard to the plane of symmetry of the pertainingelectrolytically effective working surface 19 extending through the toolaxis and are also symmetrically located with regard to the longitudinalcentral plane of the pertaining electrolytically effective workingsurface 19, which longitudinal central plane extends at a right anglewith regard to the tool axis. The guiding as well as the spacer strips21 and also the guiding and spacer strips 23 consist of electricallynonconductive material with good sliding properties.

At the ends of the sliding strips 14, there are respectively providesannular springs 26 formed, for instance, by a rubber ring andsurrounding all sliding strips. These springs 26 are arranged incircumferential grooves of the tool body 1 and also in grooves of thesliding strips 14, 15 which last mentioned grooves are in alignment withsaid first mentioned grooves so that the sliding strips 14, 15 are atboth ends radially inwardly loaded by springs 26, the cathode segments18 have their inner surfaces 27 which are as to their curvature adaptedto the outer circumference, in completely returned condition placedagainst the circumference of the central section 8 of the workpiecebody.

Provided in bore 12 of the workpiece body 1 is a control or adjustingdevice for the honing stone 16 and a feeding device for the cathodesegments 18. These two devices are connected to each other by a frictionclutch 28 in the front end section 7 of the workpiece body 1.

The adjusting device for the honing stone 16 comprises an actuating bar29 which is located in the tool axis and is displaceably mounted inaxial direction. Actuating bar 29 is accessible through a section 30 ofthe bore 12 which section is located in the clamping cone 2 and in thethread section 3 as well as in the collar 4, but has its pertaining endcompletely located inside the tool body 1. Mounted onto the actuatingbar 29are three conical control members 31 which, in the specificillustrated embodiment, are formed by two sleeves which are respectivelyconnected by two radial pins 32 but, if desired, may also form one piecewith the actuating bar 29. Each control member 31 has a front conicalsection 33 with mantle lines converging toward the front tool end andwith a rear cylindrical section 43. The adjusting elements 31' arearranged at equal distances substantially in the area of the centralsection 8 of the workpiece body. The control surface 33 of each controlelement 31 engages the counter surfaces 34 of all sliding strips 14distributed over the circumference. The said counter surfaces 34 extendat an incline with regard to the axis of the tool. These countersurfaces 34 are provided on the radially inwardly located edges of thesliding strips 14. By means of sections 43, the control members 31 areguided in the bore section 13.

When the actuating bar 29 is displaced relative to the tool body 1 inthe direction toward the front tool end, the sliding strips 14 are, bymeans of the control surfaces 33 of the adjusting members 31, pressedoutwardly against the thrust of springs 26 in such a way that theworking diameter of the honing stones 16 is correspondingly increased. 1

In a bore 36 which is located inthe front and substantially in that endof the actuating bar 29 which is located in the central section 8 of thetool body, there is displaceably mounted a further actuating bar 37 ofthe feeding device for the cathode segments 18, for displacement in theaxial directionof the tool. This actuating bar 37 is connected to theactuating bar 29 through the friction clutch 28. Between two adjacentcontrol elements 31 each of the adjusting devices for the honing stones26, there is displaceably mounted on the actuating bar 29 a controlmember 38 of the feeding device for the'cathode segments 18. Thiscontrol element 38 is so displaceably mounted that in the presentinstance two such control elements 38 are provided. These controlelements 38 are respectively, by means of a diametrical pin 39 extendingthrough two axial slots 40 in the mantle of the outer actuating bar 29,positively connected to the inner actuating bar 37. As a result thereof,the control elements 38 are adapted to be moved in axial directionrelative to the control elements 31. The control elements 38 aresubstantially of the same design as the control elements 31 which meansthat they have a front cone-shaped section 41 and a rear cylindricalsection 42. The diameter and the angle of the cone 41 equal the diameterand the angle of the cone 33, whereas the outer diameter of the cylindrical section 42 equals that of the cylindrical section 43. As a resultthereof, also the control elements 38 are guided in the bore section 13.The sliding strips 15 have at their inner edges inclined edge sections44 which correspond to the sliding strips 14 and by means of which theyengage the conical surfaces 41 of the control elements 38 of the feedingdevice so that as a result of axial movement of the actuating bar 37 inthe direction toward the front tool end, the cathode segments 16 aremoved radially outwardly whereby the working diameter of theelectrolytically effective working surface is increased. When bothactuating bars 29, 37 are adjusted simultaneously and to the sameextent, the honing stones 16 and the cathode segments 18 carry outsubstantially identical radial movements.

Clutch 28 has a clutch sleeve 45 which is displaceable in the section ofbore 12 which is provided in the front section 7 of the tool body 1. Bymeans of this clutch sleeve 45 the actuating bar 37 is guided, whereasthe actuating bar 29 by means of its annular end face 46 arranged on itsfront end engages the rear end face of the clutch sleeve 45 so that theclutch sleeve 45 will be taken along by the actuating bar 29 during aforward movement of the bar 29. In the bore of the clutch sleeve 45which narrows down as to its inner diameter at the rear end thereof tothe diameter of the actuating bar 37, there is provided a frictionsleeve 47 which may consist, for instance, of rubber elastic material.Friction sleeve 47 has on one hand its rear end face resting against theinner end face 48 of the clutch sleeve 45,

and has its front end face resting against a pressure ring 49 which isdisplaceably arranged in the sleeve bore.

The front region of the clutch sleeve 45 has an inner threadhavingmounted therein a clamping spindle 50 with a corresponding threadsection. By means of the clamping spindle 50, the friction sleeve 47which surrounds the actuating bar 37 in a frictional connection may betensioned or squeezed or relieved by the pressure ring 49 in such a waythat the friction relative to the circumference of the actuating bar 37is either increased or decreased. For purposes of preventing thecoupling sleeve 45 from turning, a radial pin 52 provided in the frontsection 7 of the tool body engages an axial slot 51 arranged on thecircumference of said clutch sleeve 45. A helical pressure spring 53rests against the front end face of the clutch sleeve 45, said spring 53being located in the bore 12 of thetool body. By means of this spring53, the clutch sleeve 45 and thus the actuating bar 29 are spring urgedtoward the rear starting position.

When the actuating bar 29 is in the described manner displaced in thedirection toward the front tool end, it takes along the actuating bar 37in the same direction by means of the friction clutch 28 until thesliding surfaces 22, 24 of the guiding and spacer elements 21, 23 withsuch high surface pressure engage the workpiece surface to be machinedthat the force of clutch 28 which brings about this taking along will beovercome. If then, the mechanically effective working surfaces 17 of thehoning stones 16 do not yet engage the workpiece surface to be machined,only the actuating bar 29 moves so that only the honing stones 16 arefed. In the course of the machining of the workpiece, the honing stones16 wear considerably more than the guiding and/or spacer members 21, 23so that by actuation of a single actuating bar only, namely, theactuating bar 29, the mechanically and electrolytically effective toolelements are fed in conformity with said different wear.

The tool body 1 is, for instance, by an insulation of syntheticmaterial, completely covered from its rearward cylindrical section 6 tothe front end with the exception of the working surfaces l7, l9 and thesliding.

surfaces 22, 24. This insulation comprises two sleeves 54 of syntheticmaterial which are placed upon the cylindrical sections 6, 7 and areconnected thereto by means of radial screws 55. The said two sleeves 54have those end zones 56 thereof which face each other extend over therespective pertaining annular spring 26. The central section 8 of thetool body 1 is in the axial range of the guiding strips 21 covered up bysleeve segments 57 of synthetic material. These segments 57 arerespectively located between a guiding strip 21 and the respectiveadjacent honing stone 16 and are connected to the tool body 1 by meansof screws 58 which in axial direction are arranged one behind the other.The front end of the tool body 1 has an outer threaded section 59 whichis reduced in diameter and on which has been screwed an insulating cap60 by means of a corresponding inner thread, said insulating cap 60consisting, for instance, of polypropylene. The end face of said cap 60extends up to that end face of the front insulating sleeve 54 whichfaces said first mentioned front end face. The pot-shaped insulating cap60 servesfor supporting the front end of the helical pressure spring 53and has a bore 61 through which extends from the tool into the openingthe clamping spindle 50 as well as the front end of the actuating bar37, which front end is journaled in said spindle 50. In this way, theclamping spindle 50 which has its front end, for instance, provided withkey surfaces, is adapted from the outside of the tool and withoutdifficulties to be turned for adjusting the follower force of thefriction clutch 28. The cylindrical sections 6, 7 of the tool body 1have axial slots 62 which are located symmetrically with regard to thesliding strips 15. These axial slots 62 are covered toward the outsideby the respective pertaining insulating sleeve 54. Highly flexiblecopper strands 63 are arranged in said axial slot 62 and have one endprovided with a cable shoe 64 which by means of a screw 65 is connectedto the bottom of the pertaining axial slot 62, in other words to thetool body 1. The other end of the copper strand 63 which issubstantially axis parallel to the tool is inserted into a bore 67 atthe end side. This bore 67 is provided in the respective sliding striplocated in the same axial plane and is connected by soldering so that ahighly satisfactory current conduction from the tool body 1 to thecathode segments 18 will be assured.

According to the embodiment illustrated in FIG. 3, a smaller sleeve 68of a corresponding outer diameter is displaceably mounted in thecoupling sleeve 45a of the friction clutch 28a. The rear open end ofsaid sleeve 68 forms a cage for clamping balls 470, which on one handengage the inner surface of the coupling sleeve 45a, and on the otherhand engage the conical surface of a cone 69. Cone 69 is, for instance,by means of a diametrical pin arranged on the actuating bar 37a of thefeeding device for the electrolytically effective tool elements. Thecage sleeve 68 and the cone 69 are spring urged toward each other by ahelical pressure spring 49a which in its turn rests on one hand on cone69 and on the other hand against the front annularshaped end of sleeve68 by means of which the actuating bar 37a is guided. By means of spring49a, the clamping balls 47a are pulled toward the cone 69 and therebyare pressed radially outwardly against the inner surface of the couplingsleeve 45 a so that in response to an actuation of the actuating bar 29aof the adjusting device for the mechanically effective tool elements,the actuating bar 37a is frictionally taken along until the counterpressure acting upon the guiding and/or spacer elements becomes so highthat the coupling sleeve 45a will by overcoming the clamping force ofthe clamping balls47a be displaced relative to sleeve 68 and therebyrelative to the actuating bar 37a.

By changing the preload of spring 49a, for instance, while employing oneof the spindles corresponding to the clamping spindle 50, the carryingalong force of the friction clutch 28a can likewise be varied.

The tool described above is suitable in particular for electrolyticallyhoning of workpiece bores, especially long workpiece bores while thecathode surfaces 19 will, with each tool stroke, protrude entirely fromthe bore and the electrolyte feeding and discharging operation iseffected through the workpiece clamping device.

It is, however, also possible that the cathode surfaces have at leastthe length of the workpiece bore and the lifting height as it ispreferably advantageous for the machining of short workpiece bores.Furthermore, the honing tool may also be provided with an electrolytefeeding and discharging device, which device is provided in the honingtool. Furthermore, the design according to the invention may also beprovided on a honing tool for the machining of outer surfaces.

It is, of course, to be understood that the present invention is, by nomeans, limited to the showing in the drawing, but also comprises anymodifications within the scope of the appended claims.

What is claimed is:

1. Apparatus for mechanical and electrochemical machining surfaces ofmetallic workpieces, a tool body, first tool means provided with thetool body for mechanically machining a workpiece, second tool meansprovided with the tool body for electrochemically machining a workpiece,each of said first and second tool means having work surfaces, separatefeed means adjustable by differing amounts and journalled by the body inlocation transverse to the work surfaces of said first and second toolmeans respectively, said second tool means being secured in a particularadjusted position by said feed means pertaining thereto to assureagainst movement in feeding direction and also against movement contrato feeding direction, clutch means positively effective for couplingsaid separate feed means together, and an actuator means of said feedmeans for said second tool means being connected on output side thereofwith said clutch means.

2. Apparatus according to claim 1 in which work surface of said firsttool means compared with work surface of said second tool means providesgreater axially extending magnitude.

3. Apparatus according to claim 1 in which saidclutch means includesadjustable coupling resistance provision.

4. Apparatus according to claim 1 in which said first and second toolmeans have counter surfaces, and actuating bar means provided withadjusting surfaces engaged by said counter surfaces and provided to beadjustable axially of the tool body, said actuating bar means beingcoupled together by said clutch means.

5. Apparatus according to claim 1 in which first adjusting surface meansalternately in axial direction of the tool body being provided for saidfirst tool means for mechanical machining and second adjusting surfacemeans alternately in axial direction of the tool body being provided forsaid second tool means for electrochemically machining.

6. Apparatus according to claim 5 in which one adjusting surface meansis provided more for said first tool means than for said second toolmeans.

7. Apparatus according to claim 1 in which annular spring means at leastengages all movable tool means in common.

8. Apparatus according to claim 1 in which said feed means are locatedessentially entirely within the tool body and adjusting bars thereofdirectly adjoining each other.

9. Apparatus according to claim 8 in which said adjusting bars arelocated coaxially telescopic in said feed means.

10. Apparatus according to claim 8 in which internally located adjustingbars of said feed means for said second tool means and-a sleeve formedcontrol means thereof are connected together by at least one pin guidedin an axial slit of an outer adjusting bar.

11. Apparatus according to claim 1 in which said feed means areessentially identically embodied.

12. Apparatus according to claim 1 in-which said clutch means includes acoupling sleeve positively connected with an adjusting bar of said feedmeans of said first tool means at least in feeding-in direction ofmovement, and a force-locking member supported on said coupling sleeve.

13. Apparatus according to claim 12 in which said force-locking membercomprises a friction sleeve arranged in said coupling sleeve andsurrounding the adjusting bar of said feed means of said second toolmeans in force-locking connection.

14. Apparatus according to claim 12 in which a clamping spindle isprovided for said force-locking member of said clutch means.

15. Apparatus according to claim 14 in which said clamping spindlecomprises an externally actuated spindle sleeve surrounding an adjustingbar of said feed means of said second tool means, and guide meansbetween said coupling sleeve and said spindle sleeve.

16. Apparatus according to claim 12 in which said force-locking membercomprises at least one clamping body supported by cone means locatedinside said coupling sleeve and connected with an adjusting bar of saidfeed means for said second tool means, said clamping body and said conemeans being resiliently biased against each other into a couplingposition.

17. Apparatus according to claim 1 in which an adjusting bar of saidfeed means of said second tool means is resiliently biased againstfeed-in direction of movement.

18. Apparatus according to claim 1 in which said clutch means isprovided remote from clamping location of said tool body in axialdirection adjacent to work surfaces pertaining thereto.

19. Apparatus according to claim 1 in which an adjusting bar of saidfeed means of said second tool means protrudes beyond an end of saidtool body remote from the clamping end thereof.

20. Apparatus according to claim 19 in which said second tool meanscomprises at least one spacer member projecting over a pertaining worksurface and including electrically insulating material to engage againstthe work surface, there being several spacer members distributedperipherally of said tool body on said second tool means.

21. Apparatus according to claim 20 in which said several spacer membersare adhesively secured in recess-forming means.

22. Apparatus according to claim 20 in which at least one spacer memberis provided in axial direction adjoining electrochemically effectiveworksurface.

23. Apparatus according to claim 22 in which the electrochemicallyeffective work surface extends only less than half axial distance ofmechanically effective work surface and being located approximatelysymmetrical to middle of axial extension of mechanical work surface.

24. Apparatus according to claim 22 in which in axial direction of thetool body adjacent to the electrolytically effective work surface thereis provided at least one spacer member having a guiding surfacepreferably located in the continuation of a guiding surface of thespacer member which is provided in the region of the electrolyticallyeffective work surface, and a guiding element formed by a strip having aguiding surface which equals in width preferably the width of themechanically effective work surface.

- 25. Apparatus according to claim 24 in which the guiding element inparticular consists of electrically non-conductive material connecteddirectly to a pertaining sliding member, preferably in a recess.

26. Apparatus'according to claim 24 in which in the axial direction onboth sides of the electrolytically effective work surface there areprovided spacer members, which preferably by means of their ends whichface away from the electrolytically effective work surface extend inaxial direction as far as the pertaining ends of the mechanicallyeffective work surface.

27. Apparatus according to claim 24 in which the spacer member islocated'symmetrically with regard to the central plane which passesthrough the axis of the tool and pertains to the respective pertainingelectrochemically effective tool means.

28. Apparatus according to claim 27 in which the tool body with theexception of the areas of the work surfaces and as the case may be ofthe sliding surfaces is substantially completely covered by anelectrical insulation connected thereto, which insulation is preferablyformed by insulating sleeves in the direction of the tool axis, beingadjacent on both sides to the work surfaces, said insulating sleevesbeing located between the guiding surfaces and the mechanicallyeffective work surfaces, and an insulating cap at that end of the toolbody which faces away from the clamping end of the tool means, the partsof the insulation being detachably connected.

29. Apparatus according to claim 28 in which an actuating bar of thefeed means and optionally a clamping element of the clutch means freelyprotrude beyond that end of the tool means which faces away from theclamping end and preferably is guided by a bore in said insulating cap.

30. Apparatus according to claim 28 in which said insulating sleevesextend over two annular springs which are adjacent to the axial ends ofthe work surfaces.

31. Apparatus according to claim 24 in which said second tool means forcurrent supply is connected directly with at least one highly flexibleelectric counductor connected to a sliding member of the pertainingelectrochemically effective tool means, said sliding member consistingof electrically well-conductive material connected particularly to theelectrically conductive tool body.

32. Apparatus according to claim 31 in which a pertaining end of theelectric conductor is substantially parallel to the tool axis and isinserted into a bore provided at the end of the electrochemicallyeffective tool means and extends outside the tool means, especially inan axial groove of the too] body, the axial groove being covered by thepertaining insulating sleeve.

33. Apparatus according to claim 32 in which a clamping end of the toolbody has an electric contact surface formed by a clamping cone andadjacent to the contact surface there is provided a trapezoidal thread.

1. Apparatus for mechanical and electrochemical machining surfaces ofmetallic workpieces, a tool body, first tool means provided with thetool body for mechanically machining a workpiece, second tool meansprovided with the tool body for electrochemically machining a workpiece,each of said first and second tool means having work surfaces, separatefeed means adjustable by differing amounts and journalled by the body inlocation transverse to the work surfaces of said first and second toolmeans respectively, said second tool means being secured in a particularadjusted position by said feed means pertaining thereto to assureagainst movement in feeding direction and also against movement contrato feeding direction, clutch means positively effective for couplingsaid separate feed means together, and an actuator means of said feedmeans for said second tool means being connected on output side thereofwith said clutch means.
 2. Apparatus according to claim 1 in which worksurface of said first tool means compared with work surface of saidsecond tOol means provides greater axially extending magnitude. 3.Apparatus according to claim 1 in which said clutch means includesadjustable coupling resistance provision.
 4. Apparatus according toclaim 1 in which said first and second tool means have counter surfaces,and actuating bar means provided with adjusting surfaces engaged by saidcounter surfaces and provided to be adjustable axially of the tool body,said actuating bar means being coupled together by said clutch means. 5.Apparatus according to claim 1 in which first adjusting surface meansalternately in axial direction of the tool body being provided for saidfirst tool means for mechanical machining and second adjusting surfacemeans alternately in axial direction of the tool body being provided forsaid second tool means for electrochemically machining.
 6. Apparatusaccording to claim 5 in which one adjusting surface means is providedmore for said first tool means than for said second tool means. 7.Apparatus according to claim 1 in which annular spring means at leastengages all movable tool means in common.
 8. Apparatus according toclaim 1 in which said feed means are located essentially entirely withinthe tool body and adjusting bars thereof directly adjoining each other.9. Apparatus according to claim 8 in which said adjusting bars arelocated coaxially telescopic in said feed means.
 10. Apparatus accordingto claim 8 in which internally located adjusting bars of said feed meansfor said second tool means and a sleeve formed control means thereof areconnected together by at least one pin guided in an axial slit of anouter adjusting bar.
 11. Apparatus according to claim 1 in which saidfeed means are essentially identically embodied.
 12. Apparatus accordingto claim 1 in which said clutch means includes a coupling sleevepositively connected with an adjusting bar of said feed means of saidfirst tool means at least in feeding-in direction of movement, and aforce-locking member supported on said coupling sleeve.
 13. Apparatusaccording to claim 12 in which said force-locking member comprises afriction sleeve arranged in said coupling sleeve and surrounding theadjusting bar of said feed means of said second tool means inforce-locking connection.
 14. Apparatus according to claim 12 in which aclamping spindle is provided for said force-locking member of saidclutch means.
 15. Apparatus according to claim 14 in which said clampingspindle comprises an externally actuated spindle sleeve surrounding anadjusting bar of said feed means of said second tool means, and guidemeans between said coupling sleeve and said spindle sleeve. 16.Apparatus according to claim 12 in which said force-locking membercomprises at least one clamping body supported by cone means locatedinside said coupling sleeve and connected with an adjusting bar of saidfeed means for said second tool means, said clamping body and said conemeans being resiliently biased against each other into a couplingposition.
 17. Apparatus according to claim 1 in which an adjusting barof said feed means of said second tool means is resiliently biasedagainst feed-in direction of movement.
 18. Apparatus according to claim1 in which said clutch means is provided remote from clamping locationof said tool body in axial direction adjacent to work surfacespertaining thereto.
 19. Apparatus according to claim 1 in which anadjusting bar of said feed means of said second tool means protrudesbeyond an end of said tool body remote from the clamping end thereof.20. Apparatus according to claim 19 in which said second tool meanscomprises at least one spacer member projecting over a pertaining worksurface and including electrically insulating material to engage againstthe work surface, there being several spacer members distributedperipherally of said tool body on said second tool means.
 21. Apparatusaccording to claim 20 in which said several spacer members areadhesively secured in recess-formIng means.
 22. Apparatus according toclaim 20 in which at least one spacer member is provided in axialdirection adjoining electrochemically effective work surface. 23.Apparatus according to claim 22 in which the electrochemically effectivework surface extends only less than half axial distance of mechanicallyeffective work surface and being located approximately symmetrical tomiddle of axial extension of mechanical work surface.
 24. Apparatusaccording to claim 22 in which in axial direction of the tool bodyadjacent to the electrolytically effective work surface there isprovided at least one spacer member having a guiding surface preferablylocated in the continuation of a guiding surface of the spacer memberwhich is provided in the region of the electrolytically effective worksurface, and a guiding element formed by a strip having a guidingsurface which equals in width preferably the width of the mechanicallyeffective work surface.
 25. Apparatus according to claim 24 in which theguiding element in particular consists of electrically non-conductivematerial connected directly to a pertaining sliding member, preferablyin a recess.
 26. Apparatus according to claim 24 in which in the axialdirection on both sides of the electrolytically effective work surfacethere are provided spacer members, which preferably by means of theirends which face away from the electrolytically effective work surfaceextend in axial direction as far as the pertaining ends of themechanically effective work surface.
 27. Apparatus according to claim 24in which the spacer member is located symmetrically with regard to thecentral plane which passes through the axis of the tool and pertains tothe respective pertaining electrochemically effective tool means. 28.Apparatus according to claim 27 in which the tool body with theexception of the areas of the work surfaces and as the case may be ofthe sliding surfaces is substantially completely covered by anelectrical insulation connected thereto, which insulation is preferablyformed by insulating sleeves in the direction of the tool axis, beingadjacent on both sides to the work surfaces, said insulating sleevesbeing located between the guiding surfaces and the mechanicallyeffective work surfaces, and an insulating cap at that end of the toolbody which faces away from the clamping end of the tool means, the partsof the insulation being detachably connected.
 29. Apparatus according toclaim 28 in which an actuating bar of the feed means and optionally aclamping element of the clutch means freely protrude beyond that end ofthe tool means which faces away from the clamping end and preferably isguided by a bore in said insulating cap.
 30. Apparatus according toclaim 28 in which said insulating sleeves extend over two annularsprings which are adjacent to the axial ends of the work surfaces. 31.Apparatus according to claim 24 in which said second tool means forcurrent supply is connected directly with at least one highly flexibleelectric counductor connected to a sliding member of the pertainingelectrochemically effective tool means, said sliding member consistingof electrically well-conductive material connected particularly to theelectrically conductive tool body.
 32. Apparatus according to claim 31in which a pertaining end of the electric conductor is substantiallyparallel to the tool axis and is inserted into a bore provided at theend of the electrochemically effective tool means and extends outsidethe tool means, especially in an axial groove of the tool body, theaxial groove being covered by the pertaining insulating sleeve. 33.Apparatus according to claim 32 in which a clamping end of the tool bodyhas an electric contact surface formed by a clamping cone and adjacentto the contact surface there is provided a trapezoidal thread.